Panasonic WH-UD07CE5-A Service Manual page 104

17.5.19. Compressor Overheating (F20)
Malfunction Decision Conditions:
During operation of cooling and heating, when temperature above 112°C is detected by the compressor tank temperature
sensor.
Malfunction Caused:
1. Faulty compressor tank temperature sensor.
2. 2/3 way valve closed.
3. Refrigerant shortage (refrigerant leakage).
4. Clogged expansion valve or strainer.
5. Faulty outdoor unit PCB (main).
6. Faulty compressor.
Abnormality Judgment:
Continue 4 times in 30 minutes.
104